Brain discovery ‘aids understanding’ of high blood pressure link to dementia

Scientists have identified the regions of the brain that are damaged by high blood pressure and may contribute to the development of dementia.

Experts said the finding is a “step forward in our understanding of the concerning link between high blood pressure and cognitive decline”.

It is the first time these regions have been identified by scientists and experts will now look at the specific parts of the brain in more detail with a view to find new ways to treat mental decline among people with high blood pressure.

In the future, academics hope that the findings will help predict memory loss and dementia among people with high blood pressure.

Researchers studied patients in a number of different ways to draw their conclusions.

They examined brain scans, conducted analysis on people’s genes and also looked at observational data on thousands of patients.

They then checked their findings against another group of patients in Italy.

Lead author Tomasz Guzik, professor of cardiovascular medicine at the University of Edinburgh and Jagiellonian University Medical College in Krakow, Poland, said: “By using this combination of imaging, genetic and observational approaches, we have identified specific parts of the brain that are affected by increases in blood pressure, including areas called the putamen and specific white matter regions.

“We thought these areas might be where high blood pressure affects cognitive function, such as memory loss, thinking skills and dementia.

“When we checked our findings by studying a group of patients in Italy who had high blood pressure, we found that the parts of the brain we had identified were indeed affected.

“We hope that our findings may help us to develop new ways to treat cognitive impairment in people with high blood pressure.

“Studying the genes and proteins in these brain structures could help us understand how high blood pressure affects the brain and causes cognitive problems.

“Moreover, by looking at these specific regions of the brain, we may be able to predict who will develop memory loss and dementia faster in the context of high blood pressure.

“This could help with precision medicine, so that we can target more intensive therapies to prevent the development of cognitive impairment in patients most at risk.”

High blood pressure has previously been linked to dementia and damage to brain function and the new study, published in the European Heart Journal, shows for the first time exactly how high blood pressure damages the brain and the specific regions affected.

The international team of researchers examined MRI scans from more than 30,000 people taking part in the UK Biobank study.

They also looked at genetic information from UK Biobank participants as well as people involved in two separate studies.

The researchers identified changes to nine parts of the brain which were related to high blood pressure and worse cognitive function.

The changes included decreases in brain volume, changes to connections between different parts of the brain and changes in measures of brain activity.

The regions which appeared to be affected include a round structure in the base of the front of the brain called the putamen, which is responsible for regulating movement and influencing various types of learning.

Other areas affected include the anterior thalamic radiation, anterior corona radiata and anterior limb of the internal capsule, which are regions of white matter that connect and enable signalling between different parts of the brain.

The anterior thalamic radiation is involved in executive functions, such as the planning of simple and complex daily tasks, while the anterior corona radiata and the anterior limb of the internal capsule are involved in decision-making and the management of emotions.

Co-author of the study Professor Joanna Wardlaw, head of neuroimaging sciences at the University of Edinburgh, said: “It has been known for a long time that high blood pressure is a risk factor for cognitive decline, but how high blood pressure damages the brain was not clear.

“This study shows that specific brain regions are at particularly high risk of blood pressure damage, which may help to identify people at risk of cognitive decline in the earliest stages, and potentially to target therapies more effectively in future.”

Commenting on the study, Professor James Leiper, associate medical director at the British Heart Foundation, which funded the research, said: “By identifying specific areas of the brain which are damaged by high blood pressure, researchers have taken a significant step forward in our understanding of the concerning link between high blood pressure and cognitive decline.

“The nine brain areas identified can become nine new points of focus for further research on how high blood pressure causes damage.

“Cognitive decline can be very debilitating and scary for those patients suffering from it.

“By continuing to improve our understanding of how the changes in these brain areas affect cognitive function, we could potentially find new ways of stopping many people with high blood pressure from having to experience it.”

Dr Timothy Rittman, senior research fellow at Alzheimer’s Research UK, added: “High blood pressure is very common and, if untreated, can increase the risk of certain forms of dementia in later life.

“This study starts to unravel the reasons why this is by using sophisticated statistical methods to draw a link between high blood pressure, problems with memory and thinking, and – for the first time – shrinkage in specific parts of the brain.

“It could lead to new ways to measure the damage that blood pressure has on the brain, which could have a very big impact in helping reduce dementia risk.

“That’s because, if the early signs of damage to the brain could be spotted early, we can potentially slow this down with better blood pressure monitoring and treatment.

“This research also underlines how crucial it is to treat high blood pressure to keep our brains healthy as we age.”

In a separate study, researchers say they have developed a form of the omega-3 fatty acid docosahexaenoic acid (DHA) that is capable of crossing into the eye’s retina – layer at the back of the eye – to ward off sight loss related to Alzheimer’s disease, diabetes and other disorders.

The DHA found in fish oil capsules and other supplements is typically in a form called triacylglycerol (TAG) DHA.

While this has benefits in other parts of the body, it does not reach the eyes because it cannot travel from the bloodstream into the retina, experts say.

In the recent study researchers created a new form of DHA, or LPC-DHA.

The researchers tested their LPC-DHA supplement in mice bred to exhibit processes similar to those found in early-onset Alzheimer’s disease.

After six months, the animals that were fed LPC-DHA daily showed a 96% improvement in retinal DHA content as well as preserved retinal structure and function.

The findings were presented at the annual meeting of the American Society for Biochemistry and Molecular Biology, in Seattle.